Update pydocstyle from 1.1.1 to 2.0.0

Author: pyup-bot

requirements-dev.txt

@@ -10,7 +10,7 @@ django-appconf==1.0.2
 flake8==3.3.0
 isort==4.2.5
 mccabe==0.6.1             # via flake8
-pydocstyle==1.1.1
+pydocstyle==2.0.0
 pep8-naming==0.4.1
 pep8==1.7.0               # via flake8
 py==1.4.33                # via pytest